1. Technical Field
The present invention relates to an ink composition, an ink jet recording apparatus and an ink jet recording system.
2. Related Art
There has been known an ink jet recording apparatus that ejects very small droplets of an ink composition through nozzles of a recording head onto a recording medium to form images or characters for recording information. The ink composition used for such recording is typically an ink jet ink composition containing various constituents such as a coloring material, a surfactant, water and an organic solvent.
For performing ink jet recording, various characteristics are required of the ink composition, the recording apparatus, the recording medium and so forth. For example, in order to prevent the degradation of recording quality resulting from unstable ejection of the ink composition, it is desirable that air bubbles be not easily formed in the ink composition in the ink jet recording apparatus.
For example, JP-A-10-130556 discloses an ink composition containing an anionic surfactant having a polyoxyethylene alkyl ether acetate skeleton, or a nonionic surfactant having an alkylolefindiol skeleton. According to this patent document, the ink composition in an ink flow channel of a recording apparatus allows air bubbles therein to be easily removed when the ink flow channel is made of a plastic. JP-A-05-125314 and JP-A-05-125315 teach that an ink composition whose wettability to the flow channel has been enhanced by adding a dye capable of acting as a surfactant and a monohydric alcohol to the ink composition allows air bubbles therein to be easily removed and can satisfactorily fill the flow channel without forming bubbles.
On the other hand, recording heads having a high-density structure are developed for high density recording. Accordingly, various components of ink jet recording apparatuses are being made of silicon materials, which are easy to microfabricate. The art disclosed in JP-A-10-130556 is effective in the use of hydrophobic plastic flow channels. It is however thought that the ink composition cannot exhibit sufficient wettability to a silicon member or any other hydrophilic member, and that air bubbles are not sufficiently removed. In the art disclosed in JP-A-05-125314 and JP-A-05-125315, the dye acts as at least part of the surfactant in the ink composition. Therefore, the wettability of the ink composition is likely to be insufficient to the components of a high-density recording head. Also, in JP-A-05-125314 and JP-A-05-125315, dyes that can act as surfactant are used in color ink compositions. Therefore, applicable dyes are limited, and the hue of the color ink composition is not sufficiently adjusted.